282 Journal of Comparative NeurologV. 



more or less. Part of these fibers distribute to the skin along- 

 with the branches of the r. buccalis destined for the pit-organs 

 under and in front of the nasal sac. The remainder of the fibers 

 of the second branch accompany a few buccal fibers for pit- 

 organs about the extreme cephalic end of the supra-orbital 

 canal. They distribute to the skin of the same region and 

 farther caudad. The branch (i) goes forward to the tip of the 

 snout without giving off and any branches. It then passes 

 through the premaxillary bone. Some of its fibers enter the 

 alveolar canal of this bone and doubtless supply its teeth, while 

 the greater part distribute to the upper lip and the terminal 

 buds with which it is plentifully supplied. It is clear, there- 

 fore, that this branch (i) is composed chiefly of communis 

 fibers, and that it corresponds to the communis element of the 

 r. maxillaris of Menidia. 



The r. mandibularis trigemini. Just after the infra-orbital 

 trunk has emerged from the cranium and as it is dividing into 

 its component rami, the r. mandibularis V gives off a large mo- 

 tor nerve which turns both cephalad and caudad in the m. ad- 

 ductor mandibulae to supply its several muscular slips. This 

 consumes most, but not all, of the motor fibers of the r. man- 

 dibularis V. 



Together with the last a large sensory (general cutaneous) 

 twig is given off from the r. mandibularis V, which runs ceph- 

 alad directly under the eye ball and over the m. adductor man- 

 dibular and laterally of the -parent nerve. This twig is followed 

 at once by two other smaller ones, one sensory and one motor. 

 And a little farther cephalad, under the caudal part of the eye- 

 ball, most of the remainder of the motor fibers separate. The 

 two motor twigs enter the cephalic part of the m. adductor 

 mandibula,' and need concern us no further. The two sensory 

 twigs give off minute branches which supply the skin under 

 the eye. 



Under about the middle of the orbit, i. e., at about the 

 level at which the n. opticus enters the eye ball, the r. mandi- 

 bularis V turns outward and downward away from tho maxillary 

 and buccal rami between slips of the m. adductor mandibulae. 



